What is the frequency of #f(theta)= sin 3 t - cos 9 t #?

1 Answer
Oct 11, 2016

#3/(2pi)#

Explanation:

Period of sin 3t is #(2pi)/3# and period of cos 9t is #(2pi)/9#. To find the period of sin 3t - cos 9t, we have to see where the two periods match up. It is obvious that #(2pi)/9# will repeat it self 3 times to match with #(2pi)/3#. Hence the period T of the given function is #(2pi)/3#. To get the frequency, it would be #1/T# , that is #3/(2pi)#